Tetracycline antibiotics are a kind of broad-spectrum antibiotics for oral use, which are generated by Actinomycete-Streptomyces fermentation. They have good pharmacological action against rickettsia, many Gram-positive and Gram-negative bacteria, lymphogranuloma venereum pathogens, inclusion conjunctivitis pathogens and psittacosis pathogens.
In the early 1990s, a class of new tetracycline drugs (named as glycyclines) was developed, and its representative drug was tigecycline (GAR-936), which had broad antibacterial spectrum. Tigecycline not only has the same antibacterial activity as the previous tetracyclines, but also has an antibacterial activity to the pathogens that have been resistant to tetracyclines due to efflux mechanism and ribosomal protection mechanisms. Up to now, no oral tigecycline drug can be available in the market.

In addition, WO2013013505 A1 discloses a compound represented by the following formula (I),

Its chemical name is (4S,4aS,5aR,12aS)-9-(3-azabicyclo[3.1.0]hexan-3-ylmethyl)-4,7-bis(dimethylamino)-3,10,12,12a-tetrahydroxy-1,11-dioxo-1,4,4a,5,5a,6,11,12a-octahydrotetracene-2-carboxamide. This compound has a broad antibacterial spectrum and a high antibacterial activity.
WO2013013505 A1 further discloses a preparation process for the compound represented by formula (1). Said process can produce an amorphous form of the compound represented by formula (1) (FIG. 13), but cannot produce any crystal form of the compound represented by formula (1).